Some Basic Concepts Of Chemistry

Question 1

What is chemistry?

Answer 1

Chemistry is the study of matter , it’s physical and chemical properties and physical and chemical changes undergoes under different condition.

Question 2

Which subject is a central science and why it is ?

Answer 2

Chemistry is the central science , which provides us the knowledge of studies of physics, biological science, applied science and space , earth science and so on

Question 3

What is the scope of chemistry?

Answer 3

In every aspect of life for example, the air , the food , clothing, transportation, fluid we drink and fuel supplies and so on….

Question 4

Which instrument expanded our knowledge of chemistry in technological development?

Answer 4

Sophisticated instrumeny

Question 5

Applied science?

Answer 5

Medicine, dentistry, engineering, agriculture

Question 6

What is organic chemistry?

Answer 6

Study of properties and reaction of compounds of carbon.

Question 7

What is inorganic chemistry?

Answer 7

Study of all substances which are not organic

Question 8

What is physical chemistry?

Answer 8

Study of principal underlying, atoms , molecules,and fundamental concepts related to electron and dynamics therein and deals with the study of matter .

Question 9

What is matter

Answer 9

A substance which occupies space and mass

Question 10

Classification of matter

Answer 10

Matter are classified into pure substance and mixtures

Question 11

What is pure substance and mixture

Answer 11

Pure substance:- definite chemical composition and fixed properties

Example:- metals , non metals and metalloid.

Mixture :- Don’t have a chemical composition and the properties are not definite or fixed.

Example:- homogenous and heterogeneous

Question 12

Pure substance classification:-

Answer 12

Divided into two are elements and compounds

Elements:- can not be broken down into simpler by ordinary chemical

Example :- carbon , helium , sodium, hydrogen

Elements classified into three are metals, nonmetals and metalloid.

Question 13

What is compound ?

Answer 13

Substance broken down into simpler substance

Example:- water breaks into hydrogen and oxygen.

Question 14

What is homogenous

Answer 14

When the particle if solute dissolve in the solvent completely to form a solution , it’s is called homogenous mixture.

Question 15

What’s is states of matter ?

Answer 15

It exist in gas , liquid and solid

Solid :- atoms and molecules are tightly packed in held to perfect order or definite shape and volume

Liquid:- atoms and molecules are close to each other so they move around within the liquid

Gas :- atoms and molecules are far apart as compared to those liquid and solid .

Question 16

What is unit

Answer 16

The arbitraity decided and universally accepted standards

Question 17

How many laws are there

Question 18

Laws of conservation of mass by whom and scientists origin

Answer 18

Total mass of reactants = total mass of products

Mass not be created or not be destroyed

Scientists:- Antoine lavoisier
French

Father of modern chemistry

Question 19

Law of definite properties

Answer 19

Scientists:- French, Joseph Proust

States that a given compund always contain exactly the same proportion of elements by weight .

Question 20

Law of multiple proportion

Answer 20

Scientists:- John Dalton

When two elements combine to form two or more compounds the different of mass of one element which combine with the fixed mass of the other is in the ratio of simple whole number

Question 21

Gay lussac law of gaseous volume

Answer 21

When gas combine are produced in a chemical reaction they do so in a simple ratio by volume provided all gases are at the same temperature and pressure.

1volume = 50ml

Question 22

Avagadro law

Answer 22

Equal volumes of all gases at the same temperature and pressure contain equal number of molecules

2 volume = 2 molecules

Question 23

Dalton atomic theory

Answer 23

1) matter is made up of tiny indivisible particles is called atoms

2) atoms can neither be created or not be destroyed

3) atoms of the same elements are same

4) a compound is form by the union of atom of different elements in fixed ratio

5) a chemical reactions take place by reorganization of atoms

Question 24

Atomic mass 1amu =?
Mass of one carbon =?
Mass of one hydrogen=?
Amu of hydrogen=?

Answer 24

1 amu is 1.66×10-24 grams

Mass of one carbon is 1.992648 × 10 -23 grams

Mass of one hydrogen= 1.67× 10-24 grams

Amu of hydrogen= 1.0078b× 10 -23 grams